Alcohols and ketones of b1- and tricyclic compounds and odorant compositions

ABSTRACT

Novel compounds of formula I and their use in flavour and fragrance compositions. 
                         
R 1  to R 13  have the meaning as described in the specification.

This invention relates to novel compounds having woody, vetiver and patchouli-like odour notes. This invention relates furthermore to a method for their production and to flavour and fragrance compositions containing them.

Compounds having woody, vetiver and patchouli-like odour notes are described in the literature, for example the class of sesquiterpenes that naturally occur in essential oils and which can be isolated by water-steam distillation of a plant or parts of a plant. This process is very cost intensive and the quality and the odour as well as the flavour characteristics of the isolated compounds may vary with the climate and the origin of the plant. Thus, there is an ongoing demand in the fragrance and flavour industry for new compounds imparting, enhancing, or improving woody, vetiver and patchouli-like notes.

Tricyclic sesquiterpenes, in particular patchoulol and derivatives thereof have been disclosed in the U.S. Pat. No. 4,011,269. The compounds described therein develop odoriferous notes the character of which is reminiscent of that of patchouli oil.

We have now found a novel class of compounds having much sought after woody, vetiver and patchouli-like odour notes and which may be produced from synthetic starting materials.

In a first aspect the invention provides a compound of the formula I

wherein

-   R¹, R⁴, R⁶ and R⁷ are independently hydrogen, methyl or ethyl; -   R² and R³ are independently hydrogen, or C₁₋₅ alkyl, e.g. methyl,     ethyl, or linear or branched propyl, butyl, or pentyl; or -   R² and R³ together with the carbon atom to which they are attached     form a 5- or 6-membered cycloylkyl ring; -   R⁵ is hydrogen, or C₁₋₄ alkyl, e.g. methyl, ethyl or linear or     branched propyl; -   R⁸ is hydrogen, or branched lower C₃₋₇ alkyl, e.g. isopropyl, tert.     butyl; -   R⁹ is hydrogen, methyl, ethyl, or branched lower C₃₋₇ alkyl, e.g.     isopropyl, tert. butyl; -   R¹⁰ is ethyl or propyl; -   R¹¹ is C ₁₋₄ alkyl, e.g. methyl, ethyl, or linear or branched propyl     or butyl; -   R¹² is hydroxy; -   R¹³ is hydrogen, or C ₁₋₄ alkyl, e.g. methyl, ethyl, or linear or     branched propyl or butyl; or R¹² and R¹³ together with the carbon     atom to which they are attached form a carbonyl group; -   the dashed line represents either a C—C single bond or no bond; and     -   a) when C5 and C8 are connected by single bond and C9 and C6 are         connected by a single bond, C9 and C5 are not connected by a         bond,         -   n=1,         -   R⁷, R⁸ are hydrogen, and         -   R⁹ is hydrogen, methyl or ethyl; or     -   b) when C5 and C8 are connected by a single bond and C9 and C6         are connected by a single bond, C9 and C5 are not connected,         -   n=0,         -   R⁷, R⁸ is hydrogen,         -   R⁹ is a branched lower C₃₋₇ alkyl; or     -   c) when C5 and C8 are not connected by a bond, C9 and C5 are         connected by a single bond,         -   R⁷ is hydrogen, methyl or ethyl,         -   R⁸ is a branched lower C ₃₋₇ alkyl, or         -   R⁷ and R⁸ together with the carbon atoms to which they are             attached form a 5- or 6-membered cycloalkyl ring,         -   n=0, and         -   the bond between C6 and C8 may be a single bond or a double             bond.

Preferred compounds are those of the formulae Ia, Ib and Ic

wherein

-   R¹, R⁴, R⁶, and R¹⁶ are independently hydrogen, methyl or ethyl; -   R⁷ and R¹⁴ are independently hydrogen, methyl or ethyl; or, -   R⁷ and R¹⁴ together with the carbon atoms to which they are attached     form a 5- or 6-membered cycloalkyl ring; -   R² and R³ are independently hydrogen, or C₁₋₅ alkyl, e.g. methyl,     ethyl, or linear or branched propyl, butyl, or pentyl; or, -   R² and R³ together with the carbon atom to which they are attached     form a 5- or 6-membered cycloalkyl ring; -   R⁵ is hydrogen, or C₁₋₄ alkyl, e.g. methyl, ethyl, or linear or     branched propyl; -   R¹⁵ is C₁₋₄ alkyl, e.g. methyl, ethyl, or linear or branched propyl; -   R¹² is hydroxy; -   R¹³ is hydrogen or C₁₋₄ alkyl, e.g. methyl, ethyl, or linear or     branched propyl; or -   R¹² and R¹³ together with the carbon atom to which they are attached     form a carbonyl group; and -   in formula Ic the bond between C6 and C8 may be a single bond, or     the dotted line together with the bond between C6 and C8 may     represent a double bond.

The compounds according to the present invention contain one or more chiral centres and as such may exist as a mixture of stereoisomers, or they may be resolved as isomerically pure forms. Resolving stereoisomers adds to the complexity of manufacture and purification of these compounds and so it is preferred to use the compounds as mixtures of their stereoisomers simply for economic reasons. However, if it is desired to prepare individual stereoisomers, this may be achieved according to methodology known in the art, e.g. preparative HPLC and GC or by stereoselective syntheses.

Particular preferred compounds of formula Ia are 1,5,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one, 1,5,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one, 1,3,3,5,7,8,8-Heptamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one, 3,3,5,7,8,8-Hexamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one, 3,3,5,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one, 5,7,8,8-Tetramethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one, and 5,6,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-ol.

A particular preferred compound of formula Ib is 1-Isopropyl-3,3,5-trimethyl-tricyclo[3.2.1.0^(2,7)]octan-6-one.

Particular preferred compounds of formula Ic are 5-Isopropyl-1,3-dimethyl-bicyclo[3.2.1]oct-3-en-2-one, 5-Isopropyl-1,3-dimethyl-bicyclo[3.2.1]octan-2-one, 5-tert-Butyl-1,3-dimethyl-bicyclo[3.2.1]oct-3-en-2-one, 5-sec-Butyl-1,3-dimethyl-bicyclo[3.2.1]oct-3-ene-2-one, 5-Isopropyl-3-methyl-bicyclo[3.2.1]oct-3-ene-2-one, 5,7-Diisopropyl -3-methyl-bicyclo[3.2.1]oct-3-en-2-one, 5-Isopropyl-3,7,7-trimethyl-bicyclo[3.2.1]oct-3-en-2-one, and 1,3,5-Trimethyl-1,5,6,7,8,8a-hexahydro-1,4a-ethano-naphthalen -2-one.

In another aspect the invention provides flavour and fragrance compositions comprising a compound of formula I or mixtures thereof, more particularly compounds of formula Ia, Ib, or Ic or mixtures thereof. Particular preferred are compositions that comprise at least one compound of formula Ia and one compound of formula Ic.

In addition, the compounds may be used in combination with a basis material. As used herein, the “basis material” includes all known odourant molecules selected from the extensive range of natural and synthetic molecules currently available, such as essential oil, alcohols, aldehydes and ketones, ether and acetals, ester and lactones, macrocycles and heterocycles, and/or in admixture with one or more ingredients or excipients conventionally used in conjunction with odourants in fragrance compositions, for example carrier materials, and other auxiliary agents commonly used in the art.

In one embodiment, the compounds of the present invention may be used in fragrance applications, e.g. in any field of fine and functional perfumery.

In another embodiment, the compounds of the present invention may be used in flavour applications and are particularly useful in modifying for example strawberry and raspberry flavours but also brown flavours. They may be used in herbal mixtures and teas. The compounds of the present invention are also well suited for example in mouthwash applications.

In flavourant applications, the compounds of the present invention may be present in compositions in amounts ranging from 0.001 to 5% by weight of a flavour composition, more preferably from 0.01 to 0.5% by weight. The compounds according to the present invention may be used for herbal flavour compositions, strawberry and raspberry compositions, brown flavour compositions, or tea compositions.

When used in fragrance applications, compounds of the present invention can be employed in wide ranging amounts depending upon the specific application and on the nature and quantity of other odourant ingredients, that may be for example, from about 0.001 to about 20 weight percent. In one embodiment compounds may be employed in a fabric softener comprising in amount of about 0.001 to 0.05 weight percent. In another embodiment compounds of the present invention may be in alcoholic solution in amounts of about 0.1 to 20 weight percent, more preferably between about 0.1 and 5 weight percent.

However, these values should not be limiting on the present invention, since the experienced perfumer and flavourist may also achieve effects or may create novel accords with lower or higher concentrations.

The compounds of the present invention may be employed into the fragrance application simply by directly mixing the fragrance composition with the fragrance application, or they may, in an earlier step be entrapped with an entrapment material, for example, polymers, capsules, microcapsules and nanocapsules, liposomes, film formers, absorbents such as carbon or zeolites, cyclic oligosaccharides and mixtures thereof, or they may be chemically bonded to substrates, which are adapted to release the fragrance molecule upon application of an external stimulus such as light, enzyme, or the like, and then mixed with the application.

Thus, the invention additionally provides a method of manufacturing a fragrance application, comprising the incorporation of a compound of formula I as a fragrance ingredient, either by directly admixing the compound of formula I to the application or by admixing a fragrance composition comprising a compound of formula I, which may then be mixed to a fragrance application, using conventional techniques and methods.

As used herein, “fragrance application” means any product, such as fine perfumery, e.g. perfume and Eau de Toilette; household products, e.g. detergents for dishwasher, surface cleaner; laundry products, e.g. softener, bleach, detergent; body care products, e.g. shampoo, shower gel; and cosmetics, e.g. deodorant, vanishing creme, comprising an odourant. This list of products is given by way of illustration and is not to be regarded as being in any way limiting.

The compounds according to the present invention may be prepared according to a process wherein appropriately substituted cyclohexenones are reacted with allyl bromide or allyl chloride under reaction conditions well known to the person skilled in the art (Bull. Chem. Soc. Jpn., 2298-2303 (1993). The resulting alkylated cyclohexenones (formula II as shown below) may be converted in the presence of ethyl aluminium-dichloride or methyl aluminium-dichloride to provide compounds of formula I wherein R¹² and R¹³ taken together represents an oxygen atom, as illustrated by compounds of formula Ia, Ib, and Ic in scheme 1. The conditions under which such Lewis acid catalyzed reactions may proceed is described for example by Snider et al. in the Journal of Am. Chem. Soc. 1980, 102, 5872-5880 which is herein incorporated by reference.

The resulting carbonyl group at C1 may be reduced and/or alkylated to give further compounds of formula I. Similarly, if there is a double bond at C6 and C8 this can be reduced in a known manner to give still further compounds of formula I.

Compounds of formula II may also be prepared by alkylation of appropiately substituted phenols by reaction of the phenol with a metal hydride and an alkenylchloride (Greuter, H. et al. (1977) Helv. Chim. Acta, 60, 1701), followed by hydrogenation.

Whether a compound of formula Ia, Ib, Ic, or a mixture thereof is formed depends on the substituent pattern R², R³, and R¹⁶ of the alkylated cyclohexenone (II). A compound of formula Ic is formed as a main product if R², R³, and R¹⁶ of formula II are hydrogen. A mixture of compounds of formula Ia and Ib as main product is performed if R² and R³ of formula II at the same time are not hydrogen. A mixture of compounds of formula Ia and Ic as main product is formed if R² and R³ of formula II are hydrogen and R¹⁶ of formula II is not hydrogen. The compounds are useful in flavour and/or fragrance compositions as mixtures, however, should one wish to use the compounds in pure form, they can be separated easily by purification processes, such as HPLC or preparative GC, according to the methodology known in the art.

The term “main product”, as used herein with reference to single compounds, refers to a product comprising at least 50% by weight of that compound, more preferably more than 75% by weight, most preferably more than 90% by weight. When this term is used in relation to a mixture of compounds, e.g. one compound of formula Ia and one compound of formula Ic, it refers to a product comprising at least 50% by weight of this mixture, more particular more than 75% by weight, most particular more than 90% by weight.

The conversion of compounds of formula II for a selective preparation of compounds of formula Ia of the present invention may also be performed by photochemical induction. Surprisingly we found that compounds of formula Ia may be formed by photochemically induced intramolecular [2+2] cycloaddition of compounds of formula I. For the photochemical induction a Hg-lamp may be used for a time period of about 1 to 15 hours. However, the induction time may depend on the solvent used and on additives such as sensitisers and Lewis acids. Preferred solvents are methanol, ethanol and iso propanol.

Thus, in another aspect the invention refers to a method of preparing compounds of formula Ia by photochemically induced cycloaddition.

Further particulars as to reaction conditions are provided in the examples.

There now follows a series of examples that illustrate the invention.

EXAMPLE 1 a) 2-Methyl-6-(3-methyl-but-2-enyl)-cyclohex-2-enone

To a solution of LDA (prepared from BuLi, 1.6 M in hexane, 75 ml, 0.12 mol and diisopropylamine, 12.2 g, 0.12 mol) in THF (50 ml) was added 2-methyl-cyclohex-2-enone (11.0 g, 0.1 mol) at −78° C. The mixture was stirred for 1 h at −78° C. and prenyl bromide 17.88 g, 0.12 mol) was added. The mixture was stirred over night, while the temperature was allowed to rise to room temperature. MTBE (50 ml) and sat. NH₄Cl were added, the organic phase was separated and washed with brine, dried (MgSO₄) and concentrated in vacuo. The residue was distilled in a Kugelrohr oven to yield 9.8 g (55%) of a slightly yellow oil.

¹H-NMR (400 MHz, CDCl₃): 6.82 (bs, 1H), 5.14-5.09 (m, 1H), 2.56-2.48 (m, 1H), 2.37-2.25 (m, 3H), 2.13-2.03 (m, 2H), 1.77 (s, 3H), 1.70 (s, 3H), 1.75-1.68 (m, 1H), 1.61 (s, 3H) ppm. ¹³C-NMR (100 MHz, CDCl₃): 201.6 (s), 144.3 (d), 135.1 (s), 133.0 (s), 121.8 (d), 46.9 (d), 27.8 (t), 27.7 (t), 25.7 (q), 25.0 (t), 17.6 (q), 16.0 (q) ppm. GC/MS (El): 178 (M⁺, 30), 168 (25), 123 (37), 110 (100), 95 (63), 83 (33), 69 (26), 53 (34), 41 (71), 39 (44). IR (ATR): 2966s, 2924s, 1672vs, 1451s, 1377s, 1181m, 1088m, 836m cm⁻¹.

b) 2.6-dimethyl-6-(3-methyl-but-2-enyl)-cyclohex-2-enone

Sodium hydride (60%, 85 g, 2.13 mol) was added portionwise to a solution of 2,6-dimethylphenol (250 g, 2.05 mol) in 2 L of toluene at 10-15° C. The resulting suspension was stirred for 45 min. The mixture was cooled to 5° C., and prenyl chloride (262 g, 2.13 mol, 85%) was added during 1.5 h keeping the temperature at 5° C. The mixture was then stirred for further 2 h at 10-15° C. Methanol (1 L) and palladium (2.5 g, 10% on charcoal) was added and the gray suspension was hydrogenated at 0.3 bar overpressure, keeping the temperature at 20-22° C. (ice bath). The suspension was then filtered through a pad of celite. The yellow filtrate was washed with water (0.5 L), aqueous sodium hydroxide (0.5 L) and brine (0.5 L), dried (MgSO₄) and concentrated in vacuo. The residue was distilled over a 5 cm Vigreux column to yield 318 g (81%, bp 78-82° C./0.05 Torr) of a colorless oil.

Odor description: fruity, grapefruit, minty, bergamot

¹H-NMR (400 MHz, CDCl₃): 6.62 (bs, 1H, 3-H), 5.06-5.11 (m, 1H, 2′-H), 2.34-2.28 (m, 2H, 4-H), 2.25-2.14 (m, 2H, 1′H), 1.91 (dt, J_(5a,5b)=13.6 Hz, J_(5a,4)=6.1 HZ, 1H, 5_(a)-H), 1.76 (s, 3H, 2-CH₃), 1.77-1.70 (m, 1H, 5_(b)-H), 1.70 (s, 3H, 4′-H), 1.59 (s, 3H, 3′-CH₃), 1.05 (s, 3H, 6-CH₃) ppm. GC/MS (El): 192 (M⁺, 16), 124 (100), 109 (74), 82 (31), 69 (40), 41 (57). IR (ATR): 2965s, 2922s, 1667vs, 1449m, 1376m, 1033m cm⁻¹.

EXAMPLE 2 5-Isopropyl-1,3-dimethyl-bicyclo[3.2.1]oct-3-en-2-one

To a solution of 2,6-dimethyl-6-(3-methyl-but-2-enyl)-cyclohex-2-enone (5.00 g, 26.04 mmol) in toluene (40 ml) was added dropwise neat EtAlCl₂ (97%, 1.5 eq., 4.96 g, 39.06 mmol). During the addition, the temperature was kept below 10° C. The brown mixture was kept at room temperature over night and was then poured on icecold saturated NH₄Cl. The mixture was extracted with MTBE, washed with brine, dried (MgSO₄) and concentrated in vacuo. The residue was distilled bulb to bulb to yield 4.50 g (90%) of an colorless oil.

Odor description: woody, patchouli, vetiver, hesperidic

¹H-NMR (400 MHz, CDCl₃): 6.86 (bs, 1H, 4-H), 1.81 (dt, J=11.0, 2.2 Hz, 1H, 8-H_(a)), 1.78-1.72 (m, 2H, 6-Ha, 7-H_(a)), 1.75 (d, J=1.6 Hz, 3-CH₃), 1.69 (sept, J=6.8 Hz, 1H, 5-CH(CH₃)₂), 1.64-1.53 (m, 2H, 6-Hb, 7-H_(b)), 1.37 (dd, J=11.0, 2.2 Hz, 1H, 8-H_(b)), 1.24 (s, 3H, 1-CH₃), 1.00 (d, J=6.8Hz, 3H, 5-CH(CH₃)CH₃), 0.93 (d, J=6.8 Hz, 3H, CH(CH₃)CH₃) ppm. ¹³C-NMR (100 MHz, CDCl₃): 205.2 (s, C-2), 151.7 (d, C-4), 133.1 (s, C-3), 52.4 (s, C-1), 51.8 (s, C-5), 50.7 (t, C-8), 34.8 (t, C-6), 34.8, (d, 5-CH(CH₃)₂), 33.3 (t, C-7), 20.7 (q, 1-CH₃), 19.0, 18.4 (2q, CH-(CH₃)₂), 15.6 (q, 3-CH₃) ppm. GC/MS (El): 192 (M⁺, 24), 177 (18), 149 (52), 136 (33), 121 (95), 110 (100), 91(46), 77 (39), 41 (41). IR (ATR): 2959s, 2867m, 1674vs, 1446m, 1362m, 1331m, 1030s cm⁻¹.

EXAMPLE 3 5-Isopropyl-1,3-dimethyl-bicyclo[3.2.1]octan-2-one

Prepared by hydrogenation of 5-isopropyl-1,3-dimethyl-bicyclo[3.2.1]oct-3-en-2-one. Mixture of 2 isomers (ratio of 5/1), main isomer: ¹H-NMR (400 MHz, CDCl₃): 2.46-2.39 (m, 1H), 2.13-2.06 (m, 1H), 1.88-1.43 (m, 8H), 1.29-1.26 (m, 1H), 1.16 (s, 3H, 1-CH₃), 1.11 (d, J=7.2 Hz, 3H, 3-CH₃), 1.04-0.97 (m, 1H), 0.92 (d, J=6.8 Hz, 5-CH(CH₃)CH₃), 0.88 (d, J=6.8 Hz, 5-CH(CH₃)CH₃) ppm. ¹³C-NMR (100 MHz, CDCl₃): 219.6 (s, C-2), 52.7 (s), 46.3 (s) 44.7 (t), 38.7 (d), 37.9 (t), 37.5 (d), 36.3 (t), 36.4 (t), 20.4 (q), 18.4 (q), 17.4(q), 16.5(q) ppm. GC/MS (El): 194 (M⁺, 14), 151 (100), 133 (11), 123(48), 93 (29), 81 (83), 69 (19), 41 (30). IR (ATR): 2958s, 2868m, 1709vs, 1458s, 1369m, 999m cm⁻¹.

Odor description: woody, ambery, ionone

EXAMPLE 4-12

The following compounds were prepared according to the synthetic procedure of Example 2 from the correspondingly substituted materials and purified by chromatography where indicated.

Mixture of 5-tert-Butyl-1,3-dimethyl-bicyclo[3.2.1]oct-3-en-2-one and 1,5,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one

Prepared as a mixture and purified by chromatography.

a) 5-tert-Butyl-1,3-dimethyl-bicyclo[3.2.1]oct-3-en-2-one

Odor description: woody, patchouli, vetiver

¹H-NMR (400 MHz, CDCl₃): 7.03 (bs, 1H, 4-H), 1.99 (ddd, J=16 Hz, 12 Hz, 5.6 Hz, 1H 8-H_(a)), 1.75 (d, J=1.6 Hz, 3-H, 3-CH₃), 1.75-1.53 (m, 5H), 1.47-1.40 (m, 1H), 1.25 (s, 3H, 1-CH₃), 0.98 (s, 9H, 5-C(CH₃)₃) ppm. ¹³C-NMR (100 MHz, CDCl₃): 204 (s, C-2), 152.6 (d, C-4), 132.3 (s, C-3), 54.2 (s), 51.9 (s), 46.9 (t, C-8), 33.5 (t), 32.9 (s, C(CH₃)₃), 30.7 (t), 25.9 (q, C(CH₃)₃), 20.7 (q, 1-CH₃), 15.5 (q, 3-CH₃) ppm. GC/MS (El): 206 (M⁺, 6), 191 (8), 149 (10), 135 (24), 124 (99), 110 (100) 91 (32), 77 (17), 57 (28), 41 (35). IR (ATR): 2961s, 2868m, 1673vs, 1467m, 1446m, 1365m, 1238m, 1030m, 879w cm⁻¹.

b) 1,5,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one

Odor description: woody, patchouli

¹H-NMR (400 MHz, CDCl₃): 2.19 (bs, 1H, 2-H), 1.78 (dd, J_(9a,9b)=12.8 Hz, J=2.0 Hz, 1H, 9-H_(a)), 1.76-1.50 (m, 4H, 3,4-H), 1.55 (d, J_(9a,9b) =12.8 Hz, 1H, 9-H_(b)), 1.05 (s, 3H, 8-(CH₃)_(a)), 0.98 (s, 3H, 5-CH₃), 0.97 (s, 3H, 7-CH₃), 0.96 (s, 3H, 1-CH₃), 0.63 (s, 3H, 8-(CH₃)_(b)) ppm. ¹³C-NMR (100 MHz, CDCl₃): 221.1 (s, C-6), 57.0 (s, C-7), 46.6 (d, C-2), 45.5 (s, C-8), 43.7 (s, C-5), 42.6 (t, C-9), 41.8 (s, C-1), 38.6 (t, C-4), 21.0 (q, 8-(CH₃)_(a)), 19.7 (2q, C-5, 8-(CH₃)_(b)), 18.1 (q, 1-CH₃), 10.8 (q, 7-CH₃) ppm. GC/MS (El): 206 (M⁺, 6) 191 (10), 124 (100), 109 (27), 97 (76), 69 (22)55 (17), 41 (31). IR (ATR): 2926m, 2862m, 1711s, 1446m, 1373m, 1004m, 761w cm⁻¹.

5-sec-Butyl-1,3-dimethyl-bicyclo[3.2.1]oct-3-en-2-one

Odor description: woody, vetiver, cedar, olibanum

Mixture of 2 isomers: ¹H-NMR (400 MHz, CDCl₃): 6.86, 6.83 (2bs, 1H, 4-H), 1.95-1.51 (m, 7H), 1.75 (s, 3H, 3-CH₃), 1.40-1.32 (m, 2H), 1.23 (s, 3H, 1-CH₃), 1.00-0.90 (m, 6H) ppm. GC/MS (El): 206 (M⁺, 8), 177 (17), 149 (41), 124 (100), 121 (82), 110 (98), 91 (42), 77 (32), 41 (43). IR (ATR): 2961s, 2865m, 1674vs, 1446s, 1364s, 1222m, 1034s cm⁻¹.

5-Isopropyl-3-methyl-bicyclo[3.2.1]oct-3-ene-2-one

Odor description: ambery, ciste, woody

¹H-NMR (400 MHz, CDCl₃): 6.88 (bs, 1H, 4-H), 2.96 (dd, J_(1,7a)=7.4 Hz, J_(1,8b)=4.6 Hz 1H, 1-H), 2.15 (m, 1H, 7-H_(a)), 1.92 (bd, J_(8a,8b)=11.2 Hz, 1H, 8-H_(a)), 1.74 (d, J=1.2 Hz, 3H, 3-CH₃), 1.72 (sept, J=6.8 Hz, 1H, 5-CH(CH₃)₂), 1.72-1.58 (m, 2H, 6-H_(a), 7-H_(b)), 1.52-1.45 (m, 1H, 6-H_(b)), 1.42 (ddd, J_(8b,8a)=11.2 Hz, J_(8b,1)=4.6 Hz, J=2.0 Hz, 8-H_(b)), 1.03 (d, J=6.8 Hz, 3H, 5-CH(CH₃)CH₃), 0.95 (d, J=6.8 Hz, 3H, 5-CH(CH₃)CH₃) ppm. ¹³C-NMR (100 MHz, CDCl₃): 204.1 (s, C-2), 152.1 (d, C-4), 133.2 (s, C-3), 51.2 (s, C-5), 50.2 (d, C-1), 43.3 (t, C-8), 34.6 (d, 5-CH(CH₃)₂), 33.8 (t, C-6), 25.5 (t, C-7), 19.0, 18.5 (2q, 5-CH(CH₃)₂), 15.2 (q, 3-CH₃) ppm. GC/MS (El): 178 (M⁺, 49), 163 (61), 135 (50), 123 (21), 107 (100), 91 (59), 79 (46), 77 (39), 67 (23), 41 (47). IR (ATR): 2957s, 2871m, 1677vs, 1447m, 1358s, 1053m, 1018m, 918s cm⁻¹.

5,7-Diisopropyl-3-methyl-bicyclo[3.2.1]oct-3-en-2-one

Odor description: woody, elemi

Mixture of the endo/exo-isomers in a ratio of 2/1; main (endo) isomer: ¹H-NMR (400 MHz, CDCl₃): 6.97 (bs, 1H, 4-H), 3.06 (dd, J=6.2, 4.4 Hz, 1H, 1-H), 2.03-1.96 (m, 2H), 1.87 (dd, J=12.8, 10.4 Hz, 1H), 1.76-1.51 (m, 3H), 1.72 (d, J=1.6 Hz, 3H, 3-CH₃), 1.39-1.33 (m, 1H), 1.00 (d, J=6.8 Hz, 3H), 0.96 (d, J=6.0 Hz, 3H), 0.91 (d, J=6.8 Hz, 3H), 0.85 (d, J=6.0 Hz, 3H) ppm. ¹³C-NMR (100 MHz, CDCl₃): 203.0 (s, C-2), 153.9 (d, C4), 134.0 (s, C-3), 54.4 (d, C-1), 50.2 (s, C-5), 48.5 (d, C-7), 44.4 (t, C-8), 39.1 (t, C-6), 34.7 (d), 32.4 (d), 22.2 (q), 21.7 (q), 18.6 (q), 18.3 (q), 15.0 (q, 3-CH₃) ppm. GC/MS (El): 220 (M⁺, 17), 205 (8), 177 (22), 151 (28), 135 (32), 121 (30), 109 (100), 107 (50), 91 (47), 77 (29), 69 (35), 41 (52). IR (ATR): 2956s, 2872m, 1673vs, 1467m, 1365s, 973m, 903m cm⁻¹.

5-Isopropyl-3,7,7-trimethyl-bicyclo[3.2.1]oct-3-en-2-one

Prepared according to Example 2 with 2,5,5-Trimethyl-6-(3-methyl-but-2-enyl)-cyclohex -2-enone as starting material.

¹H-NMR (400 MHz, CDCl₃): 6.88 (bs, 1H, 4-H), 2.52 (d, J_(1,8b)=4.4 Hz, 1-H, 1-H), 1.98 (bd, J_(8a,8b)=11.2 Hz, 1H, 8-H_(a)), 1.80 (ddd, J_(8b,8a)=11.2 Hz, J_(8b,1)=4.4 Hz, J=2.0 Hz 1H, 8-H_(b)), 1.73 (s, 3H, 3-CH₃), 1.66 (sept., J=7.0 Hz, 1H, 5-CH(CH₃)₂), 1.53 (s, 2H, 6-H), 1.19 (s, 3H, 7-(CH₃)_(a)), 0.97 (d, J=7.0 Hz, 3H, 5-CH(CH₃)CH₃), 0.91 (d, J=7.0 Hz, 3H, 5-CH(CH₃)CH₃), 0.90 (s, 3H, 7-(CH₃)_(b)) ppm. ¹³C-NMR (100 MHz, CDCl₃): 203.7 (s, C-2), 152.2 (d, C-4), 133.3 (s, C-3), 62.4 (d, C-1), 51.7 (s, C-5), 48.5 (t, C-8), 42.6 (t, C -6), 38.8 (s, C-7), 35.0 (d, 5-CH(CH₃)₂), 32.2 (q, 7-(CH₃)_(a)), 27.5 (q, 7-(CH₃)_(b), 18.5 (q), 18.2 (q) ppm. GC/MS (El): 206 (M⁺, 35), 191 (26), 163 (25), 135 (100), 121 (50), 107 (98), 91 (73), 77 (53), 69 (29), 55 (34), 41 (81). IR (ATR): 2957s, 2870m, 1676vs, 1466m, 1359m, 1048w, 885w cm⁻¹.

Odor description: woody, resin

1,3,5-Trimethyl-1,5,6,7,8,8a-hexahydro-1,4a-ethano-naphthalen-2-one

Odor description: woody, patchouli, vetiver, cedar

Mixture of two isomers; ¹H-NMR (400 MHz, CDCl₃, (1S*,4aR*,5S*,8aR*)-isomer, derived from HMQC): 6.63 (bs, 1H, 4-H), 1.77 (d, J=1.6 Hz, 3H, 3-CH₃), 1.78-1.68 (m, 3H, 8-H_(a), 9-H_(a), 10-H_(a)), 1.63-1.53 (m, 2H, ⁹-H_(b), 10-H_(b)), 1.54-1.47 (m, 1H, 6-H_(a)), 1.50-1.44 (m, 1H, 7-H_(a)), 1.45-1.35 (m, 1H, 5-H), 1.42-1.36 (m, 1H, 8a-H), 1.22-1.14 (m, 1H, 8-H_(b)), 1.16 (s, 3H, 1-CH₃), 1.08-0.94 (m, 2H, 6-H_(b), 7-Hb), 1.03 (d, J=6.8 Hz, 3H, 5-CH₃) ppm. ¹³C-NMR (100 MHz, CDCl₃): 205.0 (s, C-2), 147.2 (d, C-4), 134.7 (s, C-3) 61.3 (d, C-8a), 54.5 (s, C-1), 50.7 (s, C-4a), 41.2 (d, C-5), 34.8 (t, C-9), 33.2 (t, C-10), 31.8 (t, C-6), 25.9 (t, C-8), 21.8 (t, C-7), 18.8 (q, 1-CH₃), 16.6 (q, 5-CH₃), 15.6 (q, 3-CH₃) ppm. MS(mixture) (El): 218 (M⁺, 96), 203 (12), 190 (7), 175 (13), 161 (7), 147 (17), 124 (100), 105 (20), 95 (58), 82 (22), 67 (8), 55 (13), 41 (24).

1,3,3,5,7,8,8-Heptamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one

Prepared as a mixture and purified by chromathography.

Odor description: patchouli, vetiver, woody

¹H-NMR (400 MHz, CDCl₃): 1.96 (bs, 1H, 2-H), 1.79 (dd, J_(9a,9b)=13.2 Hz, J_(9a,4b)=2.8 Hz, 1H, 9-H_(a)), 1.66 (d, J_(9b,9a)=13.2 Hz, 1H, 9-H_(b)), 1.59 (dd, J_(4a,4b)=13.2 Hz, J=1.0 Hz, 1H, 4-H_(a)), 1.48 (dd, J_(4b,4a)=13.2 Hz, J_(4b,9a)=2.8 Hz, 1H, 4-H_(b)), 1.08 (s, 3H, 5-CH₃), 1.04 (s, 3H, 8-(CH₃)_(a)), 1.04 (s, 3H, 7-CH₃), 1.03 (s, 3H, 3-(CH₃)_(a)), 0.97 (s, 3H, 1-CH₃), 0.83 (s, 3H, 3-(CH₃)_(b)), 0.58 (s, 3H, 8-(CH₃)_(b)) ppm. ¹³C-NMR (100 MHz, CDCl₃): 221.3 (s, C-6), 58.7 (d, C-2), 56.1 (s), 53.6 (t, C-4), 44.4(s), 44.3 (s), 41.6(s), 44.1 (t, C-9), 31.3 (s), 31.3 (2q, 3-(CH₃)_(a,b)), 21.2 (q, 8-(CH₃)_(a)), 20.3 (q, 5-CH₃), 19.8 (q, 1-CH₃), 18.9 (q, 8-(CH₃)_(b)), 13.4 (q, 7-CH₃) ppm. GC/MS (El): 234 (M⁺, 28), 219 (20), 163 (15), 152 (43), 137 (62), 121 (49), 97 (199), 83 (18), 69 (25), 57 (72), 41 (69). IR (ATR): 2959m, 2919m, 2865m, 1712s, 1452m, 1374m, 1005m, 951m, 886 w cm⁻¹.

3,3,5,7,8,8-Hexamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one

Prepared as a mixture and purified by chromatography.

Odor description: ambery, woody, pine resin, Grisalva

¹H-NMR (400 MHz, CDCl₃): 2.32 (t, J=6.0 Hz, 1H, 1-H), 2.21 (d, J=6.0 Hz, 1H, 2-H), 1.90 (dd, J=13.2 Hz, 6.0 Hz, 1H, 9-H_(a)), 1.74 (dd, J=13.2 Hz, 2.6 Hz, 1H), 1.57 (d, J=13.2 Hz, 1-H), 1.48 (dd, J=13.2, 2.6 Hz, 1H), 1.17 (s, 3H), 1.04 (s, 3H), 1.00 (s, 3H), 0.97 (s, 3H), 0.84 (s, 3H), 0.64 (s, 3H) ppm. ¹³C-NMR (100 MHz, CDCl₃): 220.9 (s), 57.3 (s), 53.3 (t), 52.6 (d), 44.0 (s), 42.3 (s), 39.6 (d), 33.4 (t), 30.9 (s), 30.5 (q), 30.3 (q), 23.9 (q), 20.1 (q), 20.0 (q), 13.4 (q) ppm. GC/MS (El): 220 (M⁺, 6), 205 (5), 164 (64), 152 (37), 137 (199), 123 (19), 91 (14), 69 (26), 55 (17), 41 (46). IR (ATR): 2956m, 2924m, 2866w, 1711s, 1451m, 1373m, 1012m, 956m, cm⁻¹.

Mixture of 3,3,5,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one and 1-Isopropyl -3,3,5-trimethyl-tricyclo[3.2.1.0^(2,7)]octan-6-one

Prepared as a mixture and purified by chromatography.

a) 3,3,5,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one

Odor description: woody, patchouli, cedar, camphoraceous

¹H-NMR (400 MHz, CDCl₃): 2.61 (t, J=5.0 Hz, 1H, 7-H), 2.46 (bt, J=5.6 Hz, 1H, 2-H), 2.34 (bq, J=5.6 Hz, 1H, 1-H), 1.92 (dd, J_(9a,9b)=13.2 Hz, J_(9a,1)=5.6 Hz, 1H, 9-H_(a)), 1.73 (J_(9b,9a)=13.2 Hz, J=2.8 Hz, 1H, 9-H_(b)), 1.58 (d, J_(4a,4b)=13.6 Hz, 1H, 4-H_(a)), 1.49 (dd, J_(4b,4a)=13.6 Hz, J=2.8 Hz, 1H, 4-H_(b)), 1.32 (s, 3H, 8-(CH₃)_(a)), 1.02 (s, 3H, 3-(CH₃)_(a)), 0.97 (s, 3H, 5-CH₃), 0.82 (s, 3H, 3-(CH₃)_(b)), 0.75 (s, 3H, 8-(CH₃)_(b)) ppm. ¹³C-NMR (100 MHz, d₆-acetone): 219.0 (s, C-6), 57.6 (d, C-7), 53.2 (t, C-4), 47.2 (d, C-2), 44.3 (s, C-3), 40.7 (d, C-1), 40.6 (s, C-5), 33.6 (t, C-9), 29.9 (q, 3-(CH₃)_(a)), 29.8 (q, 3-(CH₃)_(b)), 29.8 (s, C-8), 27.1 (q, 8-(CH₃)_(a)), 21.6 (q, 8-(CH₃)_(b)), 19.8 (q, 5-CH₃) ppm. GC/MS (El): 206 (M⁺, 17), 191, (15). 150 (29), 138 (145), 123 (64), 107 (48), 83 (100), 55 (29), 41 (48). IR (ATR): 2953s, 2866m, 1716vs, 1459m, 1373m, 1105m, 1002w, 931w, 898 w cm⁻¹.

b) 1-Isopropyl-3,3,5-trimethyl-tricyclo[3.2.1.0^(2,7)]octan-6-one

Odor description: woody, cedar, vertiver, fruity, patchouli

¹H-NMR (400 MHz, C₆D₆): 1.62 (d, J=8.3 Hz, 1H, 7-H), 1.59 (dd, J_(8a,8b)=11.2 Hz, J=2.4 Hz, 1H, 8-H_(a)), 1.52 (d, J_(8b,8a)=11.2 Hz, 8-H_(b)), 1.45 (dd, J_(4a,4b)=13.6 Hz, J=2.2 Hz, 1H, 4-H_(a)), 1.26 (d, J_(4b,4a)=13.6 Hz,1H, 4-H_(b)), 1.21-1.11 (m, 2H, 2-H, 1-CH(CH₃)₂), 1.01 (s, 3H, 5-CH₃), 0.99 (s, 3H, 3-(CH₃)_(a)), 0.96 (s, 3H, 3-(CH₃)_(b)), 0.83 (d, J=6.8 Hz, 3H, CH(CH₃)_(a)(CH₃)_(b)), 0.80 (d, J=6.8 Hz, 3H, CH(CH₃)_(a)(CH₃)_(b)) ppm. ¹³C-NMR (100 MHz, C₆D₆): 212.6 (s, C-6), 52.2 (t, C-4), 46.0 (d, C -2), 42.7 (s, C-5), 40.2 (s, C-1), 34.3 (t, C -8), 34.1 (d, C-7), 32.0 (2q, 3-(CH₃)_(a,b)), 31.9 (d, 1-CH(CH₃)₂, 29.2 (s, C-3), 18.9 (q, 5-CH₃), 18.8 (q, 1-CH(CH₃)_(a)(CH₃)_(b)), 18.7 (q, 1-CH(CH₃)_(a)(CH₃)_(b))p pm. GC/MS (El): 206 (M⁺, 41), 191 (37), 151 (15), 135 (36), 109 (100), 91 (38), 77 (24), 55 (21), 41 (43). IR (ATR): 2957m, 2926m, 2867m, 1725s, 1462m, 1317m, 1171m, 917m, 866m, 834m cm⁻¹.

EXAMPLE 13 5,7,8,8-Tetramethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one

A solution of 2,6-dimethyl-6-(3-methyl-but-2-enyl)-cyclohex-2-enone (10.0 g, 52.1 mmol) in methanol (250 ml) was irradiated using a Hg-lamp during 3 h. The solvent was evaporated in vacuo and the residue distilled in a Kugelrohr oven to yield 5.0 g of a colorless oil.

Odor description: patchouli, woody, camphoraceous

¹H-NMR (400 MHz, CDCl₃): 2.54 (m, 1H, 2-H), 2.23 (t, J=5.8 Hz, 1H, 1-H), 1.88 (dd, J_(9a,9b)=12.8 Hz, J=5.6 Hz, 1H, 9-H_(a)), 1.78 (d, J_(9b,9a)=12.8 Hz, 1H, 9-H_(b)), 1.88-1.52 (m, 4H, 3,4-H), 1.17 (s, 3H, 8-(CH₃)_(a)), 1.00 (s, 3H, 5-CH₃), 0.99 (s, 3H, 5-CH₃), 0.99 (s, 3H, 7-CH₃), 0.66 (s, 3H, 8-(CH₃)_(b)) ppm. ¹³C-NMR (100 MHz, C₆D₆): 217.6 (s, C-6), 58.1 (s, C-7), 42.7 (2s, C -5,8), 41.3 (d, C-1), 40.7 (d, C-2), 38.1 (t, C-4), 34.4 (t, C-9), 23.5 (q, 8-(CH₃)_(a)), 20.4 (q, 8-(CH₃)_(b)), 20.2 (q, 5-CH₃), 17.5 (t, C-3), 11.1 (s, 7-CH₃) ppm. GC/MS (El): 192 (M⁺, 14), 177 (12), 149 (8), 124 (100), 109 (48), 93 (15), 82 (20), 69 (34), 53 (18), 41 (51). IR (ATR): 2923m, 2863m, 1710s, 1448m, 1375m, 1068m, 1020m, 1000m, 790w cm⁻¹.

EXAMPLE 14 5,6,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-ol

Prepared from 5,7,8,8-tetramethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one by reaction with methyl magnesium chloride.

Odor description: patchouli, woody, camphoraceous

¹H-NMR (400 MHz, C₆D₆): 2.23 (dd, J_(9a,9b)=13.2 Hz, J_(9a,4a)=3.2 Hz, 1H, 9-H_(a)), 2.12-2.09 (m, 1H, 2-H), 1.95 (dd, J_(1,9b)=6.8 Hz, J_(1,2)=6.0 Hz, 1H, 1-H), 1.62-1.49 (m, 3H, 4-H_(a), 3-H_(a,b)), 1.43 (dd, J_(9b,a)=13.2 Hz, J_(9b,1)=6.8 Hz, 1H, 9-H_(b)), 1.37 (s, 3H, 8-(CH₃)_(a)), 1.26-1.18 (m, 1H, 4-H_(b)), 1.21 (s, 3H, 8-(CH₃)_(b)), 1.04 (s, 3H, 6-CH₃), 0.97 (s, 3H, 5-CH₃), 0.94 (s, 3H, 7-CH₃) ppm. ¹³C-NMR (100 MHz, C₆D₆): 79.6 (s, C-6), 50.4 (s, C-7), 42.1 (s, C-8), 41.7 (d, C-1), 38.7 (d, C-2), 36.9 (s, C-5), 36.5 (t, C-9), 35.8 (t, C-4), 27.9 (q, 8-(CH₃)_(a)), 24.9 (q, 6-CH₃), 21.6 (q, 8-(CH₃)_(b)), 20.9 (q, 5-CH₃), 18.0 (t, C-3) 12.8 (q, 7-CH₃) ppm. GC/MS (El): 208 (M⁺, 1), 190 (22), 175 (28), 162 (9), 147 (48), 121 (73), 98 (59), 83 (37), 69 (19), 55 (31), 43 (100), 41 (43). IR (ATR): 3502br., 2947vs, 2902vs, 2902vs, 2869s, 1457s, 1371s, 1207m, 1110s, 1072s, 1045s, 922vs cm⁻¹.

EXAMPLE 15

A perfume for a shower gel with a woody-floral character

parts per weight Cedryl acetate 5 Citronellyl acetate 2 Linalyl acetate 20 Agrumex 20 Pheyl ethyl alcohol 40 Amyl cinnamyl aldehyde 140 Ambrettolide 5 Ambrofix 4 Bois Cedre ess. Virginie 20 Bois Gaiac ess. 10 Damascenone (10% in DPG) 6 Dipropylene glycol 10 Eucalyptus ess. 24 Galaxolide 50 BB 381 Hedione 80 Javanol 2 Lilial 30 Linalool synt. 20 Mandarine ess. 30 Moxalone 40 N 112 1 Okoumal 5 Orange terpenes dist. 60 Rose abs. Turquie 2 Rose artess abs. 10 Rose oxide (10% in DPG) 5 Super muguet 10 Vanilline (10% in DPG) 8 1,5,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one 10 1000

In this composition 1,5,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one enhances and harmonizes the woody part. It underlines the patchouli aspect but gives also a new modern woody character. The compound blends well with the floral part of the perfume and provides volume without giving a heavy impression. 

1. A compound of formula I

wherein R¹, R⁴, R⁶ and R⁷ are independently hydrogen, methyl or ethyl; R² and R³ are independently hydrogen, or C₁₋₅ alkyl; or R² and R³ together with the carbon atom to which they are attached form a 5- or 6-membered cycloylkyl ring; R⁵ is hydrogen, or C₁₋₄ alkyl; R⁸ is hydrogen, or branched lower C₃₋₇ alkyl; R⁹ is hydrogen, methyl, ethyl, or branched lower C₃₋₇ alkyl; R¹⁰ is ethyl or propyl; R¹¹ is C₁₋₄ alkyl; R¹² is hydroxy; R¹³ is hydrogen, or C₁₋₄ alkyl; or R¹² and R¹³ together with the carbon atom to which they are attached form a carbonyl group; the dashed line represents either a C—C single bond or no bond; and a) when C5 and C8 are connected by a single bond and C9 and C6 are connected by a single bond, C9 and C5 are not connected by a bond, n=1, R⁷, R⁸ are hydrogen, and R⁹ is hydrogen, methyl or ethyl; or b) when C5 and C8 are connected by a single bond and C9 and C6 are connected by a single bond, C9 and C5 are not connected, n=0, R⁷, R⁸ is hydrogen, R⁹ is a branched lower C₃₋₇ alkyl; or c) when C5 and C8 are not connected by a bond, C9 and C5 are connected by a single bond, R⁷ is hydrogen, methyl or ethyl, R⁸ is a branched lower C₃₋₇ alkyl, or R⁷ and R⁸ together with the carbon atoms to which they are attached form a 5- or 6-membered cycloalkyl ring, n=0, and the bond between C6 and C8 may be a single bond or a double bond.
 2. A compound according to claim 1 having a formula Ia

wherein R¹, R⁴, R⁶, R¹⁴ and R¹⁶ are independently hydrogen, methyl or ethyl; R² and R³ are independently hydrogen, or C₁₋₅ alkyl; or, R² and R³ together with the carbon atom to which they are attached form a 5- or 6-membered cycloalkyl ring; R⁵ is hydrogen, or C₁₋₄ alkyl; R¹⁵ is C₁₋₄ alkyl; R¹² is hydroxy; R¹³ is hydrogen or C₁₋₄ alkyl; or R¹² and R¹³ together with the carbon atom to which they are attached form a carbonyl group.
 3. A compound according to claim 1 of formula Ib,

wherein R¹, R⁴, R⁶, R¹⁴ and R¹⁶ are independently hydrogen, methyl or ethyl; R² and R³ are independently hydrogen, or C₁₋₅ alkyl; or, R² and R³ together with the carbon atom to which they are attached form a 5- or 6-membered cycloalkyl ring; R⁵ is hydrogen, or C₁₋₄ alkyl; R¹⁵ is C₁₋₄ alkyl; R¹² is hydroxy; R¹³ is hydrogen or C₁₋₄ alkyl; or R¹² and R¹³ together with the carbon atom to which they are attached form a carbonyl group.
 4. A compound according to claim I of formula Ic,

wherein R¹, R⁴, R⁶, R¹⁴ and R¹⁶ are independently hydrogen, methyl or ethyl; R⁵is hydrogen, or C₁₋₅ alkyl; R⁷ and R¹⁴ are independently hydrogen, methyl or ethyl; or, R⁷ and R¹⁴ together with the carbon atoms to which they are attached form a 5- or 6-membered cycloalkyl ring; R¹⁵ is C₁₋₄ alkyl; R¹² is hydroxy; R¹³ is hydrogen or C₁₋₄ alkyl; or R¹² and R¹³ together with the carbon atom to which they are attached form a carbonyl group; and the bond between C6 and C8 may be a single bond; or the dotted line together with the bond between C6 and C8 may represent a double bond.
 5. A compound according to claim 1 selected from the group consisting of 1,5,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one; 1,5,7,8,8-Pentamethyl-tricyclo [3.3.1.0^(2,7)]nonan-6-one; 1,3,3,5,7,8,8-Heptamethyl-tricyclo [3.3.1.0^(2,7)]nonan-6-one; 3,3,5,7,8,8-Hexamethyl-tricyclo[3.3.1.0^(2,7)]nonan -6-one; 3,3,5,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-one; 5,7,8,8-Tetramethyl-tricyclo [3.3.1.0^(2,7)]nonan-6-one, 1-Isopropyl-3,3,5-trimethyl-tricyclo [3.2.1.0^(2,7)]octan-6-one; 5-Isopropyl-1,3-dimethyl-bicyclo[3.2.1]oct-3-en-2-one; 5-Isopropyl-1,3-dimethyl-bicyclo[3.2.1]octan-2-one; 5-tert-Butyl-1,3-dimethyl-bicyclo [3.2.1]oct-3-en-2-one; 5-sec-Butyl-1,3-dimethyl-bicyclo[3.2.1]oct -3-ene-2-one; 5-Isopropyl-3-methyl-bicyclo[3.2.1]oct-3-ene-2-one; 5,7-Diisopropyl -3-methyl-bicyclo[3.2.1]oct-3-en-2-one; 5-Isopropyl-3,7,7-trimethyl-bicyclo [3.2.1]oct-3-en-2-one; 1,3,5-Trimethyl-1,5,6,7,8,8a-hexahydro-1,4a-ethano-naphthalen -2-one; and 5,6,7,8,8-Pentamethyl-tricyclo[3.3.1.0^(2,7)]nonan-6-ol.
 6. A flavour or fragrance composition comprising a compound according to claim
 1. 7. A flavour or fragrance composition comprising at least one compound selected from the group of compounds of formula Ia

wherein R¹, R⁴, R⁶, R¹⁴ and R¹⁶ are independently hydrogen, methyl or ethyl; R² and R³ are independently hydrogen, or C₁₋₅ alkyl; or, R² and R³ together with the carbon atom to which they are attached form a 5- or 6-membered cycloalkyl ring; R⁵ is hydrogen, or C₁₋₄ alkyl; R¹⁵ is C₁₋₄ alkyl; R¹² is hydroxy; R¹³ is hydrogen or C₁₋₄ alkyl; or R¹² and R¹³ together with the carbon atom which they are attached from a carbonyl group and at least one compound selected from the group of compounds of formula Ic as defined in claim
 4. 8. A flavour or fragrance composition according to claim 7 comprising 5-tert-Butyl -1,3-dimethyl-bicyclo[3.2.1]oct-3-en-2-one and 1,5,7,8,8-Pentamethyl-tricyclo [3.3.1.0^(2,7)]nonan-6-one.
 9. A fragrance application comprising the compound according to claim 1, wherein the fragrance application is a fragrance or a flavour application.
 10. A fragrance application comprising the compound according to claim 1, wherein the fragrance application is selected from the group consisting of perfume, a household product, a laundry product, a body care product, and a cosmetic product.
 11. The method of manufacturing a fragrance application or flavour application selected from: a perfume, a household product, a laundry product, a body care product or a cosmetic product which method comprises the step of: incorporating from 0.001 to 20% by weight of a compound according to claim 1 in said fragrance application or flavour application.
 12. A method of manufacturing a flavour or fragrance composition, comprising the step of incorporating a compound of formula I as defined in claim 1 to a base material.
 13. A method of manufacturing a fragranced application, comprising the incorporation of a compound of formula I as defined in claim
 1. 14. A method according to claim 13 wherein the fragranced application is selected from the group consisting of perfume, household product, laundry product, body care product and cosmetics.
 15. A process of preparing a compound of the formula I as defined in claim 1

comprising the step of reacting a compound of formula II with ethyl aluminium dichloride or methyl aluminium dichloride

wherein R¹, R⁴, and R⁶ are independently hydrogen, methyl or ethyl; R² and R³ are independently hydrogen, or C₁₋₅ alkyl; or R² and R³ together with the carbon atom to which they are attached form a 5- or 6-membered cycloylkyl ring; R⁵ is hydrogen, or C₁₋₄ alkyl; R⁷ and R¹⁴ are independently hydrogen, methyl or ethyl; or R⁷ and R¹⁴ together with the carbon atoms to which they are attached form a 5- or 6-membered cycloalkane ring; R¹⁶ is hydrogen, or lower branched C₃₋₇ alkyl, and optionally followed by the step of reduction and/or alkylation of the carbonyl group at C1.
 16. A process of preparing a compound of the general formula Ic

comprising the step of converting a compound of formula II by photochemical induction

wherein R², R³, and R¹⁶ are hydrogen; R¹, R⁴ and R⁶ are independently hydrogen, methyl or ethyl; R⁷ and R¹⁴ are independently hydrogen, methyl or ethyl; or R⁷ and R¹⁴ together with the carbon atoms to which they are attached form a 5- or 6-membered cycloalkane ring; R⁵ is hydrogen, linear or branched C₁₋₄ alkyl; R¹⁵ is linear or branched C₁₋₄ alkyl; and and optionally followed by the step of hydrogenation across the double bond at C6 and C8, and optionally followed by the step of reduction and/or alkylation of the carbonyl group at C1. 